Diseases of the nasal cavity

Abstract

Despite garnering minimal attention from the medical community overall, olfaction is indisputably critical in the manner in which we as humans interact with our surrounding environment. As the initial anatomical structure in the olfactory pathway, the nasal airway plays a crucial role in the transmission and perception of olfactory stimuli. The goal of this chapter is to provide a comprehensive overview of olfactory disturbances as it pertains to the sinonasal airway. This comprises an in-depth discussion of clinically relevant nasal olfactory anatomy and physiology, classification systems of olfactory disturbance, as well as the various etiologies and pathophysiologic mechanisms giving rise to this important disease entity. A systematic clinical approach to the diagnosis and clinical workup of olfactory disturbances is also provided in addition to an extensive review of the medical and surgical therapeutic modalities currently available.

Keywords: Anosmia; Chronic rhinosinusitis; Dysosmia; Endoscopic sinus surgery (ESS); Hyposmia; Nasal obstruction; Olfaction; Postviral olfactory loss; Sinonasal tumors; Skull base surgery.

Fig. 18.1

Esthesioneuroblastoma. Endoscopic (A) and radiologic (B) appearance of an esthesioneuroblastoma. T1-weighted, contrast-enhanced MRI with coronal views (B) demonstrates a hyperintense lesion within the left nasal cavity, contiguous with the olfactory cleft from which this lesion is known to originate. Adjacent sinus opacification is seen within the left maxillary and ethmoid sinuses due to obstruction of the outflow drainage pathway by the tumor.

Fig. 18.2

CT scan of an anterior cranial fossa meningioma. Coronal cut, bone window, noninfused CT scan of the paranasal sinuses demonstrates a soft tissue mass epicentered within the right ethmoid cavity and olfactory cleft with attenuation of the right medial orbital wall indicative of orbital dehiscence. Marked hyperostosis, which is typical of meningiomas involving the skull base, is present.

Fig. 18.3

Normal CT scan of the paranasal sinuses. Coronal cut, bone window, noninfused CT scan of the paranasal sinuses demonstrates normal sinus aeration with absence of sinus mucosal thickening as well as a patent nasal airway and olfactory cleft. Healthy appearing paranasal sinuses are characterized radiologically by an immediate transition from the bone (white) of the sinus wall to the air (black) of the sinus cavity without any intermediating soft tissue (gray) as seen in Fig. 18.1.

Fig. 18.4

Chronic rhinosinusitis (CR) with nasal polyposis. Radiologic (A) and endoscopic (B) appearance of CR with nasal polyposis (CRSwNP). Coronal cut, bone window, noninfused CT scan of the paranasal sinuses (A) demonstrates complete opacification of the nasal airway, frontoethmoidal recess, ethmoid and maxillary paranasal sinuses consistent with severe CRSwNP. Complete opacification of the olfactory cleft bilaterally is also noted. Endoscopic view (B) of the same patient reveals a significant burden of nasal polyposis extending to the nasal floor and to the anterior most limit of the nasal cavity known as the nasal vestibule, which is lined by hair bearing skin.